InterviewSolution
Saved Bookmarks
InterviewSolution
This section includes InterviewSolutions, each offering curated multiple-choice questions to sharpen your knowledge and support exam preparation. Choose a topic below to get started.
| 551. |
(a) Describe the different steps in one complete cycle of PCR. (b) State the purpose of such an amplified DNA sequence. |
|
Answer» (b) The amplified DNA sequences have the following role : (i) Application in foreign science such as settlement of paternity disputes. (ii) Determining population and genetic diversities. |
|
| 552. |
(b) If the principal source point S was to be moved a little upwards, towards the slit `S_(1)` from its usual symmetrical position with respect to the two slits `S_(1)andS_(2)` discuss how the interference pattern, obtained on the screen, would get affected. |
|
Answer» If main source is shifted towards `S_(1)` the intensity `S_(1)` will be more and central bright on the screen will not remain as bright. The path difference of two rays meeting at central of screen will no more be zero. Fringe width and position of secondary maxima and will minima will also get affected. |
|
| 553. |
(i) Calculate the distance of an objective of height h from a concave mirror of radius of curvature 20 cm , so as to obtain a real image of magnification 2. find the location of image also . (iii) Using mirror formula explain Why does a convex always produce a virtual image . |
|
Answer» (a) Given focal length ` f = ( R ) /(2) = (20)/(2) = 10 cm` Magnification `m = -(V)/(u) =-2` `rArr " " v = 2u` Using mirror formula `(1)/( f) = (1)/(v ) + (1)/(u) =-(1)/(10) =(1)/(2u) = (1)/(u) rArr (3)/(2u) =- (1)/(10)` Also `underset( v = 2 u =-3- cm)(u=- 15 cm)` (b) For a convex mirror f is positive for real object u is negtive ` (1)/(f) =(1)/(v) + (1)/(u) rArr (1)/(v) =(1)/(f ) -(1)/( u)` au u is negative so `(1)/(v)` is positive i.e., v is positive from the equation i.e., image always lie belind the mirror . Hence image is always virtual. |
|
| 554. |
A `100 mu F` capacitor in series with a `40 Omega` resistance is connected to a `100 V_(1) 60 Hz` supply. Calculate (i) the reactance (ii) the impedance and (iii) maximum current in the circuit. |
|
Answer» (i) Reactance, `X_(C)=(1)/(2pi f c)` `=(1)/(2xx3.142xx60xx100xx10^(-6))=(10^(6))/(1.2xx10^(4)xx3.142)=(10)/(0.12xx3.142)` `=(10)/(0.37704)=26.5 Omega`. (ii) Impedance, A= `sqrt(R^(2)+X_(C)^(2))` `=sqrt((40)^(2)+(26.5)^(2))=sqrt(1600+702.25)=sqrt(2302.25)=47.98 = 48 Omega`. (iii) `V_(eff)=100V` `I_(0)=(V_(0))/(Z)=(sqrt(2V_(eff)))/(Z)=(1.414xx100)/(48)=2.95A`. |
|
| 555. |
(a) Two straight long parallel conductors carry currents `I_(1)` and `I_(2)` in the same direction. Deduce the expression for the firce per unit length between them. Depict the pattern of magnetic field lines around them. (b) A rectangular current carrying loop EFGH is kept in a uniform magnetic field as shown in the figure. (i) What is the direction of the magnetic moment of the current loop ? (ii) What is the torque acting on the loop (A) maximum, (B) zero ? |
|
Answer» (b) (i) Magnetic moment will be out of the plane from the surface HEFG. (ii) Torque `=vec(M)xxvec(B)` (A) Torque is maximum when `vec(M)||vec(B)` i.e., when it gets rotated by `90^(@)`. (B) Torque is minimum when `vec(M)` and `vec(B)` are at `270^(@)` to each other. |
|
| 556. |
Fig. shows a rectangular conducting loop PQSR in which arm RS of length l is movalbe. The loop is kept in a uniform magnetic field B directed downwards perpendicular to the plane of the loop. The arem RS is moved with a uniform speed v. Deduce an expression for (i) the emf induced across the are RS.(ii) the external force required to move the arm, and (iii) the power dissipated as heat. |
|
Answer» Eddy current : Eddy currents are the currents induced in the bulk pieces of conductors when the amount of magnetic flux linked with the conductor changes. Applications : (i) Eddy current is used in designing dead beat galvanometers. (ii) Eddy currents are used in deep heat treatment of the human body. (b) (i) The emf induced across the arm RS is `e Blv` (ii) External force required is `F=BIl` (iii) The power dissipated as heat is `P=I^(2) r=((B//v)/r)^(2) r=(B^(2) l^(2) v^(2))/r` where r be the resistance of movable arm PQ of the rectangula rconductor. |
|
| 557. |
Complete the following chemical equations : (i)` P_(4) (s) +NaOH (aq) +H_(2)O (l) to` (ii) `I^(-) (aq) +H_(2)O (l) +O_(3) (g) to` |
|
Answer» (i) `P_(4 (s)) + underset( "Phosphine")(3NaOH(aq) +) 3H_(2)O(l) to PH_(3)(g) + 3NaH_(2)PO_(2)` (ii) `3I^(-) + O_(3)(g) + 2H^(+) (aq) to I_(3)^(-) + O_(2) (g) + 2H_(2)= O(l)` |
|
| 558. |
Differentiate between molarity and molality of a solution .How can we change molality value of solution in to molarity value? |
|
Answer» Molality : It is defined as the no, of moles of solute dissolved in 1 kg of solvent . Molarity : It is defined as the no. of moles of solute dissolved in 1 L of solution . |
|
| 559. |
Name the type of immunity that is present at the time of birth in humens. Explain any two ways be which it is accomplished . |
|
Answer» Innate Immunity is present at the time of birth. Innate immunity consists of four types of barriers : `{:("1. Physical barriers., 2. Physiological barriers." ),( "3. Cellular barriers. 4. Cytokine berriers." ):}` 2. Cellular barriers-Certain types of leukocytes (WBC) of our body like polymorphonuclear leukocytes (PMNL-Neutrophils) and monocytes and natural killer in the blood as well as Macrophages in tissues can Phagocytose and destroy microbes. Cytokine berriers-Virus infected cells secrete proteins called interferon which protect non-infected cells from further viral infection. |
|
| 560. |
Study the graph given below and answer the question that follow ? (i) What is relationship between dissolved oxygen and biochemical oxygen Demand (BOD) ? (ii) Mention their effect on aquatic life in the river. |
|
Answer» (i) As BOD refers to the amount of oxygen consumed if all the organic matter in one liter of water were oxidised by bacteria. Thus greater the BOD, lesser will be the dissolved oxygen in sewage discharge. (ii) Effects on aquatic life (a) It causes high mortality rate aquatic animals. (b) The excessive nutrients facilitate algel growth causing algal bloom . |
|
| 561. |
"Determination of Biological oxygen demand (BOD) can help in suggesting the quality of a water body. " Explain |
| Answer» Biological oxygen Demand (BOD) : It is the arnount of dissolved oxygen required by the aerobic organisms to break down the organic to break down the organic material present in water body at a given temperature over a certain period of time. Natural water bodies contain a certain level of organic substances that are acted upon and decomposed by microbes. Determining the BOD of the water body establishes the amount of organic content in it. Presence of more organic waste increase , indicating that the water body is establishes the amount of organic content in it. Presence of more organic waste increase the biological activity, leading to algal blooms. High BOD value indicates more microbial activity , indicating that the water body is polluterd . | |
| 562. |
Why Western Ghats in India have been declared as biological hot-spots? |
| Answer» The significance of the vVestern Ghats is that along with their biodiversity, they also support a rich environment. | |
| 563. |
What is meant by reverse osmosis?. |
| Answer» The direction of osamosis can be reversed if a pressure larger than the osmotic pressure is applied to the solution side. That is, how the pure solvet folows out the solution through the semi premeable membrance,called reverser osmosis. | |
| 564. |
Analyses shows that FeO has a non-stoichiometric composition with formula `Fe_(0.95)O_(1.00)`. Give reason. |
| Answer» In FeO , some `Fe^(2+)` ions are replaced by `Fe^(3)` ions i.e., `3Fe^(2+) -= 2 Fe^(3+)` to maintain electrical neutrality. Hence , due to metal deficiency , the compounds obtained are non-stoichiometric composition with formula `Fe_(0.95)O`. | |
| 565. |
For a reaction : `2NH_(3)(g) overset(Pt)rarr N_(2)(g)+3H_(2)(g)` Rate = k (i) Write the order and molecularity of this reaction. (ii) Write the unit of k. |
|
Answer» Order of reaction = Zero order Molecularity of reaction = 2 Unit of K = mol `L^(-1) " time"^(-1)` |
|
| 566. |
When a co-ordination compound `CrCl_(3).5H_(2)O` is mixed with `AgNO_(3)`, 2 moles of AgCl are precipitated per mole of the compound. Write (i) Structural formula of the complex. (ii) IUPAC name of the complex. |
|
Answer» (i) Structural formula of complex : `[Cr (H_(2)O)_(5)Cl] Cl_(2)` (ii) IUPAC name : Penta aqua chloridochromium (iii) Chloride. |
|
| 567. |
Complete the following chemical equations : (i) `8MnO_(4)^(-)+3S_(2)O_(3)^(2-)+H_(2)O to ` (ii) `Cr_(2)O_(7)^(2-)+3Sn^(2+)+14H^(+) to ` |
|
Answer» (i) `8MnO_(4)^(-) + 3S_(2)O_(3)^(2-)+H_(2)O rarr 6SO_(4)^(2-)+8MnO_(2) + 2OH^(-)` (ii) `Cr_(2)O_(7)^(2-) + 3Sn^(2+) + 14H^(+) rarr 2 Cr^(3+) + 3Sn^(4+) + 7H_(2)O` |
|
| 568. |
When chromite ore `FeCr_(2)O_(4)` is fuse with NaOH in presence of air, a yellow coloured compound (A) is obtained which on acidification with dilute sulphuric acid gives a compound (B). Compound (B) on reaction with KCl formed an orange colured crystalline compound (C). (i) Write the formula of the compounds (A),(B) and (C). (ii) Write one use of compounds (C). |
|
Answer» `A = Na_(2) CrO_(4)` (Sodium Chromate) Yellow coloured `B = Na_(2) Cr_(2) O_(7)` (Sodium dichromate) `C = K_(2) Cr_(2) O_(7)` (Potassium dichromate) (orange crystal) Use of potassium dichromate : It is used as a primary standard for the estimation of `Fe^(2+)` and `I^(-)` ions in redox titration. |
|
| 569. |
From the given cells : Answer the following : (i) Which cell is used in hearing aids? (ii) Which cell was used in Apollo Space Programme? (iii) Which cell is used in automobiles and inverters? (iv) Which cell does not have long life? |
|
Answer» (i) Mercury cell (ii) Fuel cells (iii) Lead storage cell (iv) Dry cell. |
|
| 570. |
Explain the following terms : (a) Chemistry of all Lanthanoids is so identical . (b) Silver atom has completely filled d- orbitals `(4d^(10))` in its ground state . How can you say that is a transition elements ? |
|
Answer» (a) All the lanthanoids have similar outer electronic configuration and show +3 oxidation state in their compounds . Therefore , all the Lanthanoids have similar chemical properties . The different lanthanoids differ mainly in the number of 4f-electrons which are burried deep in the atoms and hence , do not influence the properties . Moreover , due to lanthanoid contraction , there is very small difference in the size of all trivalent lanthanoid ions . Thus the size of their ions is also almost identical which resultsin similar chemical properties . (b) According to definition , transition elements are those which have partially filled d-subshell in their elementary states or in their one of the oxidation states . Silver ( Z = 47) can exhibit +2 oxidation state in which it has incompletely filled d-subshells . Hence , silver is regarded as transition element . |
|
| 571. |
How do antiseptics differ from disinfectants ? Give one example of each type . |
|
Answer» Antiseptics are chemical substances which prevent the growth of micro-organisms and may even kill them but are not harmful to human or animal tissues . For example , dettol. Disinfectants are chemical substances which kill micro-organisms but are not safe to be applied to the living tissues . For example phenol. |
|
| 572. |
(a) Complete the following chemical reaction equations : (i) `Fe_((aq))^(2+) + MnO_(4 (aq))^(-) + H_((aq))^(+) to ` (ii) `Cr_(2)O_(7 (aq))^(2-) + I_((aq))^(-) + H_((aq))^(+) to` (b) Explain the following observations : (i) Transition elements are known to form many interstitial compounds . (ii) With the same `d^(4)` d-orbital configuration `Cr^(2+)` ion is reducing while `Mn^(3+)` ion is oxidising . (iii) The enthalpies of atomisation of the transition elements are quite high. |
|
Answer» `5Fe_((aq))^(2+) + MnO_(4 (aq))^(-) + 8H_((aq))^(+) to Mn_((aq))^(2+) + 4H_(2)O(l) + 5Fe_((aq))^(3+)` (ii) `Cr_(2)O_(7 (aq))^(2-) + 6I_((aq))^(-) + 14H_((aq))^(+) to 2 Cr_((aq))^(3+) + 7H_(2)O(l) + 3I_(2)(g)` b (i) The transition metals form a larger number of interstitial compounds in which small atoms such a hydrogen , carbon , boron and nitrogen occupy the empty spaces (interstitial sites ) in their lattices . (iii) Due to the presence of large number of unpaired electrons in their atom, they form strong interatomic metallic bonds . Hence they have high enthalpies of atomisation . |
|
| 573. |
Calculatate the mass of compound (molar mass = `256 g mol^(-1)` be the dissolved in 75 g of benzene to lower its freezing point by ` 0 .48 k(k_(f) = 5. 12 k kg mol ^(-1)` . |
|
Answer» Given : `Delta T f = 0 . 4 K, Kf = 5.12 kg mol^(-1)` ` w_(1) = 75 gm, w_(2) = ?, M_(2) = 256 " gm mol" ^(-1)` `Delta Tf = (1000Kfw_(2))/(M_(2)xxw_(1)) = (1000xx5.12xxw_(2))/(256xx75)` ` w_(2) = (256xx75)/(0.48xx1000xx5.12) = 1.8 gm` |
|
| 574. |
Name the pathogen that causes amoebiasis in humen . Givn the symptoms and the mode of transmission of the disease. |
|
Answer» Entamoeba histolytica is a protozoan parasite in the large intestine of humen which causes amoebiasis (amoebic dysentery). Symptoms of Amoebiasis : This includes constipation, abdominal pain and cramps, stools with excess mucus and blood clots. Houseflies, act as mechanical carriers and serve to transmit the parasite from faeces of i nfected person to food and food products, there by contaminating then. Drinking water and food contaminated by the foecal matter are the main source of infection. |
|
| 575. |
Differentiate between menarche and menopause. |
|
Answer» Menarche : The reproductive cycle in the female primates (e.g monkeys,apes and human beings) is called menstrual cycle. The first menstrual cycle begains at puberty and is called menarche. One ovum is released (ovulation) during the middle of each menstrual cycle. Menopause : In human beings, menstrual cycles ceases around 50 years, of age, that is termed as menopause. Cyclic menstruation is an indicator of normal reproductive phase and extends between menarche and menopause. |
|
| 576. |
List the features that make a stable biological community. |
|
Answer» Features of stable community are as follows: (i) Communities should have greater biodiversity for greater stability. (ii) It should be able to prevent invasion by alien species. (iii) It should be able to restore itself in a short period of time. (iv) Variations should be minimal in the community. |
|
| 577. |
Mention how e-waste is produced and disposed off. Write the solution for its treatment. |
|
Answer» Irreparable computers and other electronic goods are known as electronic waste (e-wastes). E-wastes are buried in Landfills or incinerated. More than 50 per cent of the wastes of the developed world are exported to developing countries, mainly to China, India and Pakistan, where metals like copper, iron, silicon, nickel and gold are recovered during recycling process Unlike developed countries, recycling in developing countries often involves mannual participation thus exposing workers to toxic substances present in e-wastes. |
|
| 578. |
What mass of ethlene ethyelne glycol `("molar mass"=62 g mol^(-1))` must be dissolved in 5.5kg of water to lower the freezing point of from `0^(@)C to-10^(@)C` ? `(K_(f))` for water=1.86 K kg `mol^(-1)`). |
|
Answer» Here `M_(2) = 62.0" g " mol^(-1) , w_(1) = 5.50 kg` ` = 5500 g, w_(2)` = ? `K_(f) = 1.86" K " kg mol^(-1)` `Delta T _(f) = 0-(-10.0) = 10^(@) C or 10 K` Using the formual ` Delta T_(f) = K_(f) m = K_(f) m = K_(f) xx (w_(2) xx 1000)/(M_(2) xx w_(1)) ` ` 10 = (1.86 xx w_(2) xx 1000)/(62.0 xx 5500)` ` :. " "w_(2) = (10 xx 62.0 xx 5500)/(1.86 xx 1000) = (62 xx 55)/(1.86) = 1833.33" g " = 1.833 kg`. |
|
| 579. |
A metal complex having composition `Cr(NH_(3))_(4)CI_(2)Br` has been isolated in two forms A and B. The form A reacts with `AgNO_(3)` to give a white precipitate readily soluble in dilute aqueous ammonia whereas B gives a pale yellow precipitate soluble in concentrated ammonia. (i) Write the formulae of isomers A and B. (ii) State the hybridisation of chromium in each of them. (iii) Calculate the magnetic moment (spin only) of the isomer A. |
|
Answer» (a) Isomer A: `[Cr(NH_(3))_(4)BrCI]CI.` Isomer B : `[Cr(NH_(3))_(4)CI_(2)]Br.` (b) Hybridisation of Cr in isomer A and B is `d^(2)sp^(3)`. (c) Number of unpaired electrons in `Cr^(3+)(3d^(3))` is 3. Magnetic moment `=sqrt(n(n+2)) = sqrt(3(3+2)) = 2.87 BM` |
|
| 580. |
Explain the following : (a) Out of `Sc^(3+), Co^(2+) " and "Cr^(3+) "ions, only "Sc^(3+)` is colourless in aqueous solutions. (Atomic no.: Co =27, Sc = 21 and Cr =24) (b) The `E^(@)Cu^(2+)//Cu` for copper metal is positive (+0.34), unlike the remaining members of the first transition series. (c) `La(OH)_(3) " is more basic than Lu "(OH)_(3).` |
|
Answer» (a) `Co^(2) : [Ar]3d^(7) " " Sc^(3+) : [Ar]3d_^(0) " " Cr^(3+) :[Ar]3d^(3)` `Co^(2+) " and "Cr^(3+)` have unpaired electrons. Thus, they are coloured in aqueous solution. `Sc^(3+)` has no unpaired electron. Thus, it is colourless. (b) Metal copper has high enthalpy of atomisation and enthalpy of ionisation. Therefore the high energy required to convert `Cu(s) " to "Cu^(2+)(aq)` is not balanced by its hydration enthalpy. (c) Due to lanthanoid contraction the size of lanthanoid ion decreases regularly with increases in atomic size. Thus, covalent character between lanthanoid ion and `OH^(-) " increases from "La^(3+) "to "Lu^(3+)`. Thus, the basic character of hydroxides decreases from `La(OH)_(3) " to" Lu(OH)_(3).` |
|
| 581. |
Explain the use of the following : (a) NaCN in Froth Floatation Method. (b) Carbon monoxide in Mond process. (c) Coke in the extraction of Zinc from Zinc Oxide |
|
Answer» (a) NaCN is used as depressants to separate two sulphide ores (ZnS and PbS) in Froth Floatation Method. (b) Carbon monoxide forms a volatile complex of nicked, nickel tetracarbonyl. (c) Coke is used as a reducing agent to reduce zinc oxide to zinc. |
|
| 582. |
State the difference between the first trophic levels of detritus food chain and grazing food chain. |
|
Answer» Grazing food chain : In grazing food chain, green plants constitute the first step. The The plant are producers which are eaten by herbivores, which are futher eaten by carnivores . Example : grassland Ecosystem grasses `to`herbivores `to` carnivores Detritus food chai : It begins with docomposers .The detritus is eaten by decomposers like bacteria and fungi. They release the inorganic elements into the ecosystem by breaking down the complex organic matter . e. g. Mangrove trees. Detritus `to` Decomposers `to` Secondary consumers (larvea`//` nematodes) `(Protozoa// bacteria or fungi)` |
|
| 583. |
(a) What are transgenic animals ? Name the transgenic animal having the largest number amongst all the existing transgenic animals.(c) Mention any three purposes for which these animals are produced. |
|
Answer» (a) Animals that have had their DNA manipulated to possess and express an extra gene are known as transgenic animals. (b) 95% of all existing transgenic animals are mice. (c) Three purposes for which these animals are produced : (i) Normal physiology and development : Transgenic animals can be secially designed to allow the study of how genes are regulated, and how they affect the normal functions of the body and its development. (iii) Vaccines safety : Transgenic mice are being developed for use in testing the safety of vaccines before they are used on humans. |
|
| 584. |
Why do sports persons of often fall a victim to cocaine addiction ? |
| Answer» Cocaine, coommonly called coke or crack in usually snorted . It interferes with neurotransmitter dopamine . It has a potent stimulating action on central nervous system , producing a sense of euphoria and increased energt . So, the sportrmen often fall a victim to cocaine addiction but exessive dosage of cocaine causes hallucinations . These days cannabinoids are also being used by some sports person. | |
| 585. |
By the end of 2002 the public transport of Delhi switched over to a new fuel. Name the fuel. Why is this fuel considered better? Explain. |
| Answer» Delhi Government shifted to CNG (Compressed Natural Gas). CNG is better because it burns more efficiently unlike petrol or diesel, in automobiles and very little of it is left unburnt. Also CNG is cheaper fuel than petrol and diesel and cannot be adulterated like diesel and petrol and also cannot be stolen away. | |
| 586. |
How does the angle of minimum deviation of a glass prism vary, if the incident violet light is replaced with red light? |
|
Answer» `As lambda_(red) gt lambda_("violet"), so mu_(red) lt mu_("violet") and delta_(red) lt delta_("violet").` When incident violet light is replaced with red lifht , the angle of minimum deviation of glass decreases. |
|
| 587. |
Parturition is induced by a complex neuroendocrine mechanism. Explain. |
|
Answer» The process of delivery of the fetus is called parturition is induced by complex neuroendocrine machanism. The signals for parturition originate from the fully developed fetus and placenta which induce mild uterine contractions called foetal-ejection reflex. This triggers release of hormone oxytocin from the maternal pituitary. Oxytocin acts on the uterine muscles ad causes stronger uterine contractions, which in turn stinulates further secretion of oxytocin. This leads expulsion of the baby out of the uterus through the birth canal. |
|
| 588. |
Why are mango trees unable to grow in temperature climate ? |
| Answer» Mango trees are unable to grow in temperature climate because low temperature affects the kinectics of enzymes and through it the basal metabolism, activity and other physiological functions of the organism. | |
| 589. |
(a) State the objective of animals breeding. (b) List the impotance and limitations of inbreeding. How can the limitation be overcome ? (c ) Give example of a new breed each of cattle and poultry . |
|
Answer» (a) Animals breeding-objectives : 1. Improve growth rate. 2. Increased production. 3. Improve Desirable Qualities. 4. Improved resistance to diseases. 5. Improved resistance to adverse environment conditions (b) Importance : 1. Increase homozygosity 2. To evolve pureline 3. Expose harmful recessive superior genes. 5. Elimiation of less disrable genes. Limitation : 1. Reduce fertillity and productivity 2. Imbreeding depression (c) Jersey/(Cattle)-and Leghorn (Poultry). |
|
| 590. |
Describe a comspicuous change observed when (i) a solution of `NaCl` is added to a sol of hydrated ferric oxide. (ii) a beam of light is passed through a solution of NaCl and then through a sol. |
|
Answer» (i) Addition of `NaCl` is added to a sol of hydrated ferric oxide `(Fe_(2)O_(3))` causes coagualation. (ii) When a beam of light is passed through a solution of `NaCl`, no tyndall effect is produced. But when it passed through a sol. tyndal effect is produced. |
|
| 591. |
A copper-silver cell is set up. The copper ion concentration in it is 0.10 M. The concentration of silver ions is not known.The cell potential measured is 0.422 V. Determine the concentration of silver ions in the cell. [Given `E_(Ag^(+)//Ag)^(@)=0.80,E_(Cu^(2+)//Cu)^(@)=+0.34 V]` |
|
Answer» Half cell reactions : At cathod :`2Ag^(+)(aq)+2e^(-)to2Ag(s)` At anode : `Cu(s)toCu^(2+)(aq)+2e^(-)` The cell reaction is `Cu(s)+2Ag^(+)(aq)toCu^(2+)(aq)+2Ag(s)` The cell can represented as `Cu(s)|Cu^(2+)(aq)||Ag^(+)(aq)|Ag(s)` `:.E_("cell")^(@)=E_("cathode")^(@)-E_("anone")^(@)` `=0.80=0.34=0`.46V` `:.E_("cell")^(@)=E_("cell")^(@)-(0.059)/(n)"log " ([Cu^(2+)(aq)])/([Ag^(+)(aq)]^(2))` `0.422-0.46=(-0.059)/(2)"log" [-1-2[Ag^(+)]]` `-0.038=0.95+0.059" log" [Ag^(+)]` `-log[Ag^(+)]=(0.0675)/(-0.059)` `log[Ag^(+)]=1.14407` `:.[Ag^(+)]="Antilog" (1.144)` `[Ag^(+)]=13.93M` |
|
| 592. |
Whate happens in the following activities and why? (i) An electrolyte is added to a hydrated ferric oxide sol in water. (ii) A bean of light is passed through a colloidal solution. (iii) An electric current is passed through a colloidal soluidal solution. |
|
Answer» (i) When an elecrolyte like KCl is added of `Fe(OH)_(3)` sol , the positively charged colloidal particles of `Fe(OH)_(3)` get coagulated by the oppositely charged `Cl^(-)` ions provided by KCl. (ii) When a bean of strong light is passed through a colloidal solution scattering of light by colloidal particles takes place and the path of light becomes visible . this phenomenon is called Tydall effect. (iii) On passing the electric current , colloidal particles move towards the oppositely charged electrode where they lose their charge and get coagulated. |
|
| 593. |
A metallic element crystallises into a lattice having a ABC ABC …… pattern and packing of spheres leaves out voids in the lattice. What type of structure is formed by this arrrangement ? |
| Answer» Cubic Close Packing (CCP) structure is formed by ABC ABC …….. Pattern. | |
| 594. |
Name the two different categories of microbes naturally occurring in sewage water. Explain their role in cleaning sewage water into usable water. |
| Answer» Aerobic and anaerobic bacteria or fungi exist in sewage water. After the primary treatment of water, aerobic bacteria are added in -aeration tanks. Growth of these bacteria reduces BOD as they consume organic matter. Anaerobic bacteria are added in anaerobic sludge digesters, where these digest the sludge and form biogas, etc.. | |
| 595. |
Explain the response of all communities of environment over time. |
| Answer» Environmental factors like temperature, water, light, soil, etc., may influence the members of communities in varying degrees. Organism in response to these factors shall try to adapt according to their capacities. In this process, they may try to maintain a constant internal environment through homeostasis or migrate to a less stressful environment or may even suspend activities till favourable conditions return. | |
| 596. |
List the two types of immunity a human baby is born with. Explain the differences between the two types. |
|
Answer» The two types of immunity are innate and passive immunity. Innate Immunity is a non-specificty pe of defenceth at proyides barriers to the entry of antigens. Passive Immunity is a pathogen-specific type of defence that develops in response to encounter with pathogen. The foetus receives antibodies through the placenta. |
|
| 597. |
Why are some molecules called bioactive molecules ? Give two examples of such molecules. |
| Answer» These molecules which are biologically active are called bioactive molecules. Like antibiotics and vitamins are bioactive molecules.e.g., Citric acid - Aspergillus niger Ethanol Saccharomyces Cerevisiae. | |
| 598. |
1. What stimulates pituitary to release the hormone responsible to, parturition ? Name the hormone. |
| Answer» Parturition is induced by a eomplex neuro endocrine mechanism. The signals for parturition originate from the fully developed fetus and the Placenta which induce mild uterine contraction called foetal ejection reflex. This triggers release of oxytocin from the maternal pitujtuary. Oxytoin is the hormone responsible for parturition. | |
| 599. |
Pollinating species of wasps show mutualism with specific 5g plants. Mention the benefits the female wasps derive from the fig trees from such an interaction |
| Answer» The female wasp uses the fruit not only as an ovipositian (egglaying) site but also uses the developing seeds within the fruit for nourishing its larvae. The wasp pollinates the fig inflorescence while searching for suitable egg-laying site. In return for the favour of pollination the fig offers the wasp its devleoping seeds, as food for the developing wasp Larvae | |
| 600. |
What is inbreeding depression and how is it caused in organisms ? Write any two advantages of inbreeding. |
|
Answer» Inbreeding depression Inbreeding exposes harmful recessive genes that are eliminated by selection. It also helps in accumulation of superior genes and elimination of less desirable genes. Therefore, in this approach, there is selection at each step, increases the productivity of inbreed population. However, continued inbreeding especially close breeding, usually reduces fertility and even productivity. This is called inbreeding depression. Advantages Of Inbreeding : 1. Inbreeding brings the homozygosity in the population so it helps in producing a pure line of ammals. 2. It helps in accumulation of superior genes and elimination of less desirable genes. It increases the productivity of inbred population. |
|